The present invention relates to a thrust bearing for use in a strut suspension and an automotive suspension for a vehicle.
In a strut suspension which connects a wheel to a vehicle body, a shock absorber is provided for absorbing or damping vibrations of a spring interposed between the vehicle body and the road wheel. The shock absorber has a cylinder and a strut piston rod and is designed to damp the vibrations of the spring by virtue of resistance produced when the strut piston rod is retracted into the interior of the cylinder.
A cylindrical bounce stopper made of a rubber elastic element is provided in such a manner as to cover an outer circumference of the strut piston rod of the shock absorber, and the bounce stopper has a function to control the relative movement of the cylinder and the strut piston rod. Vibrations and impact from the road wheel are absorbed by virtue of the elastic deformation of the rubber elastic element.
Then, a porous elastic element formed of such as expanded urethane rubber is used for the bounce stopper in order to obtain good riding comfort while absorbing the vibrations of the vehicle.
Incidentally, thrust bearings are provided on strut suspensions of the vehicle between struts and the vehicle body for holding road wheels on both sides while following pivot motions of strut rods when the road wheels are steered (for example, Patent Document No. 1).
As shown in FIG. 8, when a thrust bearing 81 is mounted on a strut piston rod 85, a gap is produced between an inner circumferential surface 82 of the thrust bearing 81 and the strut piston rod 85.    Patent Document No. 1: Japanese Utility Model Registration No. 2501751
As shown in FIG. 8, when the porous elastic element formed of such as expanded urethane rubber is used as the bounce stopper 83 in order to obtain good riding comfort while absorbing the vibrations of the vehicle body, a problem occurs in which muddy water or the like 87 absorbed into the bounce stopper 83 intrudes into the interior of the bearing from the gap between the piston rod 85 and the inner circumferential surface 82 of the thrust bearing 81.